Never dull ...

... and never vague: Freeman Dyson explores the farthest limits of human imagination. (Hat tip, Dave Lull.)

For instance, in Last and First Men (1931) Olaf Stapledon imagined Martians as little green clouds composed of tiny droplets – sub-vital units that could transmit and receive fields, and serve as muscles and nerves to make the cloud behave as a coherent individual. It was a nice, spooky idea more than once picked up by movie-makers, but Dyson turns it into neurophysiology.
To understand what is going on in the brain we need "observing instruments that are local, non-destructive, and non-invasive, with rapid-response, high-bandwidth and high spatial resolution. We need to invent the terrestrial equivalent of a Martian sub-vital unit." And then he adds "There is no law of physics that declares such an observational tool to be impossible." And then with help from his sub-vital units, he proposes communication by radiotelepathy.